A new, air-stable, permanently porous uranium(IV) metal–organic framework U(bdc)₂ (1, bdc²⁻ = 1,4-benzenedicarboxylate) was synthesized and its H₂ and CH₄ adsorption properties were investigated. Low temperature adsorption isotherms confirm strong adsorption of both gases in the framework at low pressures. In situ gas-dosed neutron diffraction experiments with different D₂ loadings revealed a rare example of cooperative framework contraction (ΔV = −7.8%), triggered by D₂ adsorption at low pressures. This deformation creates two optimized binding pockets for hydrogen (Q_st = −8.6 kJ mol⁻¹) per pore, in agreement with H₂ adsorption data. Analogous experiments with CD₄ (Q_st = −24.8 kJ mol⁻¹) and N,N-dimethylformamide as guests revealed that the binding pockets in 1 adjust by selective framework contractions that are unique for each adsorbent, augmenting individual host–guest interactions. Our results suggest that the strategic combination of binding pockets and structural flexibility in metal–organic frameworks holds great potential for the development of new adsorbents with an enhanced substrate affinity.

中文翻译：

---

自调节结合袋增强了铀基金属有机框架中 H2 和 CH4 的吸附。

合成了一种新型空气稳定、永久多孔铀( IV )金属有机骨架U(bdc) ₂ ( 1 , bdc ²⁻ = 1,4-苯二甲酸)，并研究了其H ₂和CH _{4吸附性能。}低温吸附等温线证实了两种气体在低压下在框架中的强烈吸附。_{不同D 2}负载量的原位气体剂量中子衍射实验揭示了低压下D ₂吸附引发的协同骨架收缩的罕见例子（Δ V = -7.8%） 。这种变形为每个孔创建了两个优化的氢结合袋 ( Q _st = -8.6 kJ mol ^{-1 )，与 H} ₂吸附数据一致。以 CD ₄ ( Q _st = -24.8 kJ mol ^-1 ) 和N , N -二甲基甲酰胺为客体的类似实验表明， 1中的结合口袋通过每种吸附剂独特的选择性框架收缩进行调整，增强了个体主客体相互作用。我们的结果表明，金属有机框架中结合袋和结构灵活性的战略组合对于开发具有增强的底物亲和力的新型吸附剂具有巨大的潜力。